Failure Diagnosis Circuit, Vibrator Device, And Physical Quantity Sensor

Abstract

A failure diagnosis circuit, which performs failure diagnosis on a reference voltage generation circuit, monitors a reference voltage supplied from the reference voltage generation circuit to a first circuit, and diagnoses that the reference voltage generation circuit fails when a state in which the reference voltage is not within a predetermined range continues for a predetermined time.

What is claimed is: 
     
         1 . A failure diagnosis circuit that performs failure diagnosis on a reference voltage generation circuit, wherein
 the failure diagnosis circuit monitors a reference voltage supplied from the reference voltage generation circuit to a first circuit, and diagnoses that the reference voltage generation circuit fails when a state in which the reference voltage is not within a predetermined range continues for a predetermined time.   
     
     
         2 . The failure diagnosis circuit according to  claim 1 , wherein
 the first circuit is an analog-digital conversion circuit that converts an analog signal into a digital signal.   
     
     
         3 . The failure diagnosis circuit according to  claim 1 , wherein
 the first circuit is a physical quantity signal processing circuit that outputs a drive signal for driving a physical quantity detection element for detecting a physical quantity, and generates a detection signal corresponding to the physical quantity based on an output signal of the physical quantity detection element.   
     
     
         4 . The failure diagnosis circuit according to  claim 2 , wherein
 the reference voltage temporarily fluctuates in at least one of a timing at which the analog-digital conversion circuit starts sampling of the analog signal and a timing at which the analog-digital conversion circuit ends the sampling.   
     
     
         5 . The failure diagnosis circuit according to  claim 3 , wherein
 the reference voltage temporarily fluctuates in at least one timing of a rising edge and a falling edge of the drive signal.   
     
     
         6 . The failure diagnosis circuit according to  claim 3 , wherein
 the reference voltage temporarily fluctuates in at least one timing of a rising edge and a falling edge of a control signal for controlling the physical quantity signal processing circuit.   
     
     
         7 . The failure diagnosis circuit according to  claim 1 , further comprising:
 an abnormality determination circuit configured to determine whether the reference voltage is abnormal and output an abnormality determination signal indicating a determination result; and   a failure diagnosis signal output circuit configured to diagnose whether the reference voltage generation circuit fails based on the abnormality determination signal, and output a failure diagnosis signal indicating a diagnosis result, wherein   the failure diagnosis signal output circuit diagnoses that the reference voltage generation circuit fails when the abnormality determination signal continues for a predetermined time and the reference voltage is abnormal.   
     
     
         8 . A vibrator device comprising:
 the failure diagnosis circuit according to  claim 1 .   
     
     
         9 . A physical quantity sensor comprising:
 the failure diagnosis circuit according to  claim 1 .